The present invention relates to arbors for use with a cup shaped or cylindrical hole saw. More specifically, the present invention pertains to a retaining mechanism for use with a hole saw arbor to prevent unintended disengagement of the arbor from the hole saw during use.
A variety of hole saw arbors are known in the art. For example, the patents listed below show hole saw arbors which receive a cup shaped or cylindrical hole saw.
______________________________________ Inventor's Name U.S. Pat. No. Issue Date ______________________________________ Czyzewski 5,108,235 04/28/92 Clark 4,148,593 04/10/79 Clark et al. 4,036,560 07/19/77 Bittern 3,784,316 01/08/74 Meshulam 3,758,221 09/11/73 ______________________________________
The hole saw arbor in each of these references generally includes an arbor shaft having a pilot bit attached thereto for guiding the hole saw into a workpiece. A cup shaped or cylindrical hole saw is attached to the arbor by means of a threaded end of the shaft or a retaining flange (as shown in Meshulam). A drive collar is associated with the shaft such that the collar cannot rotate about the shaft but is, rather, driven by the shaft. Pins are provided and extend from the drive collar into the hole saw to positively retain the hole saw and drive collar in engagement.
While the devices shown in the references show some kind of spring, biased bearing, or threaded nut to hold the drive collar against the hole saw, none of these devices provide a way of securely holding the drive collar in engagement with the hole saw in a quickly disengageable manner. More specifically, the Czyzewski, Clark '593, Clark et al. '560, and Bittern references show devices which have a biased bearing or spring which acts against the drive collar to hold it in engagement with the hole saw. One problem with the devices in these references is that if sufficient force is applied to the drive collar, the spring forces will be overcome thereby disengaging the drive collar from the hole saw.
The Meshulam device uses a threaded nut to engage the shaft and hold the drive collar in engagement with the hole saw. While Meshulam provides a way of holding the drive collar in engagement with the hole saw, it requires time consuming threading and unthreading of the nut. Additionally, the threaded arrangement of Meshulam can be somewhat unreliable since threads are subject to stripping and interference from, and dirt or other particulate material.
As such, it would be desirable to provide a hole saw arbor for use with a hole saw which retains the drive collar in engagement with the hole saw and prevents unintended disengagement of the drive collar from the hole saw. Additionally, it would be desirable to provide a hole saw arbor assembly which quickly and easily releases the drive collar from the hole saw to facilitate changing of the hole saw.